Implement visualizing the quad tree in a separate window

This window creation still sucks a bit, we should realize it
without actually showing it.

Graphics/Diagram/Gtk.hs

@@ -40,3 +40,11 @@ diagS :: DiagProp -> MeshString -> Diagram Cairo R2
 diagS p mesh
   | alg p == 2 || alg p == 3 = diag p. Objects . facesToArr $ mesh
   | otherwise = (diag p . Object . meshToArr $ mesh) # bg white
+
+
+-- |Create the tree diagram from a String which is supposed to be the contents
+-- of an obj file.
+diagTreeS :: DiagProp -> MeshString -> Diagram Cairo R2
+diagTreeS p mesh
+  | alg p == 4 = mkDiag treePretty p (Object . meshToArr  $mesh)
+  | otherwise  = mempty

Graphics/Diagram/Plotter.hs

@@ -8,8 +8,10 @@ import Algorithms.RangeSearch.QuadTree
 import Algorithms.PolygonIntersection.Core
 import Data.Maybe
 import Data.Monoid
+import Data.Tree
 import Diagrams.Backend.Cairo
 import Diagrams.Prelude hiding ((<>))
+import Diagrams.TwoD.Layout.Tree
 import Graphics.Diagram.Types
 import Graphics.Gloss.Data.Extent
 import Parser.PathParser
@@ -231,6 +233,23 @@ gifQuadPath = GifDiag f
         vtf = filterValidPT p vt
 
 
+-- |A diagram that shows the full Quad Tree with nodes.
+treePretty :: Diag
+treePretty = Diag f
+  where
+    f p (Object []) = mempty
+    f p (Object vt) = prettyRoseTree (quadTreeToRoseTree (qt, []))
+      where
+        qt = quadTree (filterValidPT p vt) (dX p, dY p)
+        prettyRoseTree :: Tree String -> Diagram Cairo R2
+        prettyRoseTree t =
+          renderTree (\n -> (text n # fontSizeL 5.0)
+                        <> rect 50.0 20.0 # fc white)
+                     (~~)
+                     (symmLayout' (with & slHSep .~ 60 & slVSep .~ 40) t)
+          # scale 2 # alignT # bg white
+
+
 -- |Creates a Diagram that shows an XAxis which is bound
 -- by the dimensions given in xD from DiagProp.
 xAxis :: Diag